The invention relates generally to a process for coating fibers, and more specifically to a process for making metal oxide coatings on graphitic carbon fibers and other graphitic material.
Carbon fibers, particularly carbon-graphite fibers, are increasingly valuable as reinforcing materials in a variety of composite structural materials. A common problem with carbon fibers is that the carbon is very susceptible to oxidation especially on graphite basal plane edges, which seriously impairs the desired physical and mechanical properties of the carbon fibers.
The prior art has investigated a very large variety of coating processes and other methods for making carbon fibers more oxidatiopn resistant. While much valuable work has been done, additional improvements are still needed.
It is, therefore, a principal object of the present invention to provide a process for depositing metal oxide coatings on the surface of graphite fibers and other graphitic materials.
It is an advantage of the present invention that the coating material comes from within the fiber and deposits initially at the graphite layer plane edges, thereby forming preferentially at the locations where oxidation is most rapid.
It is another advantage of the present invention that the process is simple to understand and to perform.